The aim of this study is to determine whether women receiving a gonadotropin-releasing hormone agonist (GnRH-a) during in vitro fertilization-embryo transfer have adequate pituitary desensitization to GnRH and also to determine whether serum E2 is a valid measure of this phenomenon. We are documenting in a very thorough way a specific effect of dexamethasone on pituitary function that has never in the past been reported in vovo while there are some soft data reporting such an effect in vitro, and are planning to publish shortly after the completion of the study.